Multiple shoot induction in zygotic embryos: A strategy for acceleration of banana breeding

Abstract

The presence of residual female fertility in most of the parthenocarpic banana accessions, embryo culture technique encourages the banana breeder to develop new hybrids through conventional breeding. Desirable trait can be fixed in banana in the first generation of hybrid progenies, but their evaluation is a long process owing to non-availability of uniform suckers/planting material. The duration of the breeding cycle can be reduced by developing more number of plantlets per hybrid event under in vitro embryo culture. Thus efforts were taken to standardize the multiple shoot formation from single embryo through media manipulation and decortications of embryo culture derived single plants. Success on multiple shoot formation was achieved up to 75% and 95% in seeded accessions of M.acuminata and M.velutina embryos respectively. In general, enhanced regeneration efficiency and rate of multiple shoot formation were recorded in media with BAP concentration of 17.76µm. Single in vitro plantlets derived through embryo culture were decorticated to 3 cubic cm size that resulted in 100% multiple shoot formations. This technique has been implemented from the seeds obtained from controlled pollination (18 cross combinations) and open pollination (nine accessions) of various genomic groups (ABB, AAB, AA) and their genetic fidelity of multiple shoots were also confirmed through microsatellite markers. As this technique, i) enhances the regeneration of hybrid seeds; ii) overcomes the risk of field mortality of the hybrid progenies and iii) allows simultaneous evaluation for multiple traits, will accelerate the breeding program by reducing the time taken for the release of potential banana hybrids.